Rotary pump with check valve



Dec. 16., 1969 T. s. SPRAGUE ROTARY PUMP WITH CHECK VALVE Filed Sept:15, 1987 2 Sheets-Sheet 1 FiG.

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R E V m Theodwe SSprague BY ATTORNEY United States Patent 3,483,824ROTARY PUMP WITH CHECK VALVE Theodore S. Sprague, Hudson, Ohio, assignorto The Babcock & Wilcox Company, New York, N.Y., a corporation of NewJersey Filed Sept. 15, 1967, Ser. No. 668,752 Int. Cl. F0411 3/00,15/02; F16k 15/00 US. Cl. 10389 6 Claims ABSTRACT OF THE DISCLOSURE Animproved rotary pump adaptable for circulating a substantiallyincompressible fluid through a passageway. The pump generally comprisesa housing having an extended portion adapted to extend substantiallyaxially of a portion of the passageway. A motorized drive shaft rotateswithin the housing and has a free end which extends from the extendedportion of the passageway. An impeller is mounted on the free end of theshaft for rotation by the shaft as the shaft rotates. A check valve ismounted on the pump housing at the suction side of the impeller.

BACKGROUND AND SUMMARY OF THE INVENTION In the course of designing aconsolidated nuclear steam generator which utilizes a plurality of pumpsarranged in a parallel fashion with common fluid inlet and outletheaders, it became necessary to provide for the eventuality of failureof an individual pump. Due to the parallel arrangement of the pumps, ifone pump fails it is desirable to close off the passageway occupied bythe impeller of the failed pump so that the remaining operating pump orpumps may continue to circulate fluid from the common inlet header tocommon outlet header without loss in efficiency occasioned by fluidbacking up through the passageway occupied by the inoperative pump andreturning to the common inlet header.

Commercially available check valve and pump configurations wereinvestigated and found to be unequal to the task of automaticallycompensating for the failure condition without substantially reducingpump efl'lciencies. The disclosed inventive arrangement solves theproblem in a simple and eflicient manner.

In the inventive arrangement a rotary pump is adapted to circulate fluidthrough a passageway having an inlet and an outlet. The inlet and outletmay be considered to be the common inlet and common outlet of aplurality of pumps arranged in a parallel fluid flow configuration onewith the other. The pump is provided with an elongated housing portionwhich extends axially of the passageway between the inlet and outlet.The pump shaft protrudes from the housing into the passageway and animpeller is removably mounted on the free end of the shaft for rotationwith the shaft. A plurality of vanes are pivoted to the housing withinthe passageway On the suction side of the impeller and arranged to closethe passageway when fluid backs up within the passageway. For example,in the parallel arrangement, assuming one of the pumps fails, thedischarge from the remaining operating pump causes the fluid in thecommon outlet header to back up within the portion of the passagewaywithin which the failed pump is disposed and pivot the vanes closed. Thearrangement thus closes off the passageway when a pump fails while theother pumps are operating. Additionally, when the vanes are open, aswhile the pump is operating, the vanes are arranged to direct the fluidsubstantially longitudinally of the passageway and into the pumpimpeller so that the pump efficiency is enhanced.

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It should be noted however that the inventive arrangement of the vaneswithin the passageway and with respect to the impeller is thought to beof general application to hydraulic systems. The inventive arrangementis therefore not limited to applications in nuclear reactors or parallelfluid circuits.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevation view of apump showing the check valve closed,

FIG. 1A is a schematic view of a plurality of pumps arranged inparallel,

FIG. 2 is a partial side elevation view of the pump showing the checkvalve open,

FIG. 3 is a partial plan view of the check valve taken along the line 33of FIG. 1,

FIG. 4 is a partial elevation view of the check valve taken along theline 44 of FIG. 3,

FIG. 5 is an elevation view similar to FIG. 4 showing the valve open,

FIG. 6 is a reduced plan view similar to FIG. 3 showing anotherembodiment of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawingswherein like reference numerals designate like or corresponding partsthroughout the several views there is shown in FIG. 1, a rotary pump 10adapted to circulate a substantially incompressible fluid through apassageway 11 having an inlet 12 and outlet 13. The pump 10 generallyincludes a housing 14 with an elongated annular portion 15 adapted toextend substantially axially of a portion of the passageway 11, amotorized output drive shaft 16 journalled for rotation within thehousing 14 and having a free end 17 which extends beyond the annularportion 15 of the housing, an impeller 18 removably mounted on the freeend 17 of the shaft 16 for rotation within the passageway 11 as theshaft rotates, and a plurality of vanes 19 pivotally mounted on thehousing within the passageway 11 for motion toward and away from oneanother to act as a louvered check valve on the suction side of theimpeller 18.

The passageway 11 to which the preferred embodiment is adapted is formedby an open-ended L-shaped conduit 20 having an elongated annular portion20A intermediate the inlet 12 and outlet 13. However, it is understoodthat the passageway shown is intended to be representative of anypassageway through which an incompressible fluid may be circulated andthat persons skilled in the art may adapt the device to passageways ofother construction Without departing from the spirit or scope of theinvention. Further, the annular portion may be formed by providing asleeve (not shown) within the passageway, as is well known in the art.

The conduit 21 has an opening 21 formed therein through which thehousing 14 protrudes sufiiciently to allow the impeller 18 and vanes 19to be positioned properly within the pasageway 11. It is seen that thehousing 14 is mounted on the conduit 29 and supported in place so as toclose the opening 21. In the preferred embodiment a portion of the outersurface 20F of the conduit 20 is faced to form a platform for anenlarged portion 22 of the housing 14. The enlarged portion 22, orflange, is provided with a mating surface 22F complementary to the facedsurface 20F of the conduit 20 and is mounted in place on the conduit bymeans well known in the art to form a fluid tight seal between themating surfaces.

As shown in FIGS. l3 the louver-type check valve is an annularly shapedvalve comprising a plurality of curved vanes 19 mounted on the housingfor limited rotation between an open position as shown in FIG. 2 and aclosed position as shown in FIG. 1. It is seen that the vanes aresubstantially equidistantly spaced around the housing. As best shown inFIGS. 4 and 5, each vane 19 has a rounded leading edge 27 with a curvedbody portion 28 extending therefrom which gradually tapers to a trailingedge 29 remote from the leading 27. Although in the preferred embodimentthe vanes are formed from sheet metal and are hollow. They may befabricated having a solid cross-section without departing from thespirit and scope of the invention. As best shown in FIGS. 1-3, each vane19 is freely pivotally mounted and is rotatable about an axis extendingsubstantially radially of the axis of the annular portion 15 of thehousing. The vanes 19 are individually rotatable from the closedposition to the open position and returnable to the closed position inresponse to the flow fluid within the conduit 20.

Referring now to FIGS. 3 and 6 it is seen that each vane has asubstantially straight inboard end 30 adjacent the annular housingportion 15 and a curved outboard end 31 or tip, having a curvature whichcorresponds to the contour of inner surface of the conduit 20. As viewedin the closed position shown in FIG. 3 in the preferred embodiment theinboard end 30 is formed substantially perpendicular to the axis ofrotation of the vane, the trailing edge 29 is formed substantiallyparallel with the axis of rotation of the vane next adjacent to thetrailing edge, the outboard end 31 is arcuately formed to describe aportion of the circumference of a circle concentric with the axis of theannular portion 15 of the housing, and the leading edge 27 is formedsubstantially parallel with the axis of rotation of the vane.

As best shown in FIGS. 35, the curved body portion 28 of each vanedefines an upstream surface 32 remote from the impeller and a downstreamsurface 33 adjacent the impeller. The leading edge end of each vane hada larger cross section than the trailing edge end and has a circularrecess 35 extending therethrough substantially paralel with the leadingedge of the vane. A plurality of pivot pins 36 mounted on the annularportion 15 of the housing and extending radially therefrom act assupports for the vanes. Each pin 36 is a rod having one end 37externally threaded and the other end terminated by a head portion 38.The annular portion 15 of the housing is provided with a plurality ofinternally threaded recesses 39 having axes oriented radially of theaxis of the housing to threadably receive the pins. The vane recesses 35are counterbored from the outboard end 31 to form enlarged recesses 38Ato accommodate the head portions 38 of the pins 36. The head portions 38hold the vanes in place for rotation about the pins and prevent thevanes from moving endwise of the pins. The head portion 38 is adapted toaccommodate any driving tool well known in the art for threadablyengaging the pin with the housing.

The annular portion 15 of the housing 14 is provided with a plurality ofstops 40 extending radially from the housing into the passageway. Thestops 40 are substantially equidistantly spaced around the housing andcorrespond in number of the number of vanes. Each of the stops 40defines the extreme open position for one of the vanes.

Assuming the vanes are in the closed position shown in FIG. 3, as theimpeller commences rotating, each vane commences rotation from theclosed position as fluid flows against the upstream surface 32 of thevanes and continues to so rotate until the downstream surface 33 of eachvane contacts the stop 40 corresponding thereto. A reversal of fluidflow within the passageway returns the vanes to the closed position.When the vanes are pivoted to the open position they are arranged todirect the flow of fluid longitudinally of the passageway. That is, thestops 40 are arranged to position the vanes .4 such that a line drawntangent to the upstream surface 32 of a vane at the trailing edge 29 issubstantially parallel to the axis of the passageway 11 and annularportion 15 of the housing 14.

Assuming the impeller is stationary, the vanes commence rotation fromthe open position as fluid flows against the downstream surface 33 ofthe vanes, and causes them to rotate until the upstream surface 32contacts the vane next adjacent. For example, when a plurality of pumpsare arranged in parallel with one another as shown in FIG. 1A; when onepump fails, fluid flow induced by the pumps in service will close thevanes. The vanes overlap one another and acts as stop one for the other,to define the closed position. It should be noted that when the impelleris stationary and if the vanes are in the open position, fluid flowingpast the impeler is directed towards the downstream surface 33 of thevanes at substantialy right angles thereto to afford their rapidclosure.

In accordance with the foregoing remarks it is seen that it isadvantageous to correlate the design of the curvature 'of the upstreamsurface, the position of the stops, the angle the impeller bladesdescribe with respect to the downstream surface of the vanes and theaxial distance between the impeller blades and vanes as measured alongthe axis of the annular portions of the housing, to achieve apredetermined fluid flow within the portion 20A of the pasageway 11.

In the embodiment shown in FIGS. 1-3, the annular portion 15 of thehousing 14 is substantially cylindrically shaped. As a result, when thevanes are in the closed position it is seen that a substantiallytriangular space 50 exists between the inboard end 30 of each vane andthe outer periphery of the housing. Thus a limited amount of fluid flowslongitudinally of the housing even when the vanes are in the closedposition. However, as the number of vanes utilized is increased thesummation of the incremental spaces 50 decreases and the volume of fluidflow is decreased correspondingly.

In the embodiment shown in FIG. 6 a plurality of flat surface 51 areformed on the housing. For example, the annular portion 15 of thehousing 14 may be formed having an octagonally shaped outer surface toaccommodate an eight-vaned configuration such that the inboard end 30 ofeach vane is disposed substantially parallel with respect to the outerperiphery of the housing as the vane rotates. In this embodiment theaforementioned spaces 50 are substantially completely eliminated withthe result that fluid flow longitudinally of the passageway is alsosubstantially completely eliminated when the vanes are in the closedposition.

What is claimed is:

1. An improved rotary pump adaptable for circulating a substantiallyincompressible fluid through a passageway, the pump generallycomprising, a housing having a portion formed to extend substantiallyaxially of a portion of the passageway, a motorized drive shaftrotatable within the housing, a free end of the shaft extending from theextended portion of the housing, and an impeller mounted on the free endof the shaft for rotation by the shaft as the shaft rotates, a checkvalve mounted on the pump housing at the suction side of the impellerfor closing the passageway when fluid backs up within the passageway,the check valve being an annularly-shaped valve comprising curved vanesmounted on the housing for limited rotation in place between an openposition and a closed posit1on.

2. The improvement according to claim 1 including a plurality of stopsmounted on the housing to define the open position of the vanes.

3. An improved rotary pump adaptable for circulating a substantiallyincompressible fluid through a passageway, the pump generallycomprising, a housing having a portion formed to extend substantiallyaxially of a portion of the passageway, a motorized drive shaftrotatable within the housing, a free end of the shaft extending from theextended portion of the housing, and an impeller mounted on the free endof the shaft for rotation by the shaft as the shaft rotates, a checkvalve mounted on the pump housing at the suction side of the impellerfor closing the passageway when fluid backs up within the passageway,the check valve comprising a plurality of curved vanes, a plurality ofpins mounted on the housing and extending radially thereof each pinacting as a pivot pin for one of the vanes, the vanes having an openposition in which they are arranged to direct the fluid substantiallylongitudinally of the passageway when impeller rotation induces fluidflow therein and having a closed position in which they are arranged tooverlap one another to impede the flow of fluid when fluid tends to flowin a direction opposite to impeller induced flow.

4. In a nuclear reactor, an improved rotary pump adaptable forcirculating a substantially incompressible fluid through a passageway,the pump generally comprising,

a housing having a portion for-med to extend substantially axially of aportion of the passageway, a motorized drive shaft rotatable within thehousing, a free end of the shaft extending from the extended portion ofthe housing, and an impeller mounted on the free end of the shaft forrotation by the shaft as the shaft rotates, a check valve mounted on thepump housing at the suction side of the impeller for closing thepassageway when fluid backs up within the passageway, the check valvecomprising a plurality of pins mounted on the extended portion of thehousing and extending radially thereof on the suction side of theimpeller, a plurality of vanes, each vane being pivotally mounted on oneof the pins, the vanes having an open position and a closed position, aplurality of stops mounted on the extended portion of the housing andextending radially thereof on the suction side of the impellerintermediate the impeller and pins, each stop defining the open positionof one of the vanes, the vanes being arranged to overlap one another todefine the closed position for each of the vanes, the vanes rotatingfrom the closed position to the open position when the impeller inducesfluid flow within the passageway and from the open position to theclosed position when fluid tends to flow in the passageway in adirection opposite to the direction of impeller induced flow.

5. An improved rotary pump adaptable for circulating a substantiallyincompressible fluid through a passageway, the pump generallycomprising, a housing having a portion formed to extend substantiallyaxially of a portion of the passageway, a motorized drive shaftrotatable within the housing, a free end of the shaft extending from theextended portion of the housing, and an impeller mounted on the free endof the shaft for rotation by the shaft as the shaft rotates, a checkvalve mounted on the pump housing at the suction side of the impellerfor closing the passageway when fluid backs up within the passageway andopening in response to the impeller induced flow, the check valve beingan annularly-shaped valve comprising vanes freely pivotally mounted onthe housing for limited rotation in place between an open position and aclosed position.

6. The improvement according to claim 5 wherein each vane overlaps thenext adjacent vane when they are in the closed position.

References Cited UNITED STATES PATENTS 1,683,949 9/1928 'Bergdoll.2,459,815 1/ 1949 Hammell. 3,118,467 1/1964 Kuhn 137512.1 3,160,11212/1964 Flaton et al. 2301 15 3,263,906 8/1966 Ward 137512.1

890,117 6/ 1908 Austin. 1,460,428 7/1923 Moody 16389 2,030,560 2/1936Adams 103-89 2,947,466 8/1960 Busquet.

FOREIGN PATENTS 530,741 7/1955 Italy.

HENRY F. RADUAZO, Primary Examiner

